well at least on the s197s the 3.6 pulley makes about 8psi. the best thing to do is just sign up on a mustang forum ( mustangcollective.com) and ask around their. the only two forums im really active in are this one, and that. guys over there are very knowledgable about stuff like that. or if u email vortech they can tell you.

yes the aftercoolers are very costly too.
look at www.frozenboost.com you can rig up an innercooler if you want, just gotta make sure the sizes are right. later down the road i might try to innercool mine with a FMIC.